1. Field of the Invention
The present invention generally relates to an organic electro-luminescence (to be abbreviated as “EL” hereinafter) device, and more particularly, to an organic EL device having good cooling and dehumidification functions. Such an organic EL device employs a metallic heat sink and a moisture absorber that can effectively dissipate the heat and avoid the outside moisture to remarkably prolong the lifetime of the device.
2. Description of the Prior Art
In general, the major challenge that the state-of-the-art technology in organic EL displays (also know as OELDs) is facing is that the organic layer of an organic EL device easily reacts with moisture or oxygen to thus form dark spots, which may adversely affect the luminescence efficiency. Therefore, the lifetime of an organic EL device is closely linked to the cooling condition related to the great amount of heat generated during luminescence operation. On the other hand, the second electrode is easily short-circuited to the first electrode due to improper treatment on the boundary during device fabrication. Furthermore, the precision of matrix grid positioning when organic EL devices displaying the three primary colors (red, green and blue) are fabricated also results in another problem in the industry.
In order to overcome the above problems, some companies have developed a number of prior art organic EL displays. For example, in the U.S. Pat. No. 5,952,037, entitled “Organic electroluminescent display panel and method for manufacturing the same”, there is disclosed an organic EL display panel, as shown in FIG. 1 and FIG. 2. The organic EL display panel has a plurality of emitting portions and the method for manufacturing the same comprises the steps of: forming a plurality of first display electrodes 12 on a substrate 10; forming, on the substrate 10 on which the first display electrodes 12 are formed, a first insulating layer by using a first insulating material; forming a second insulating layer by using a second insulating material; etching the second insulating layer through the openings of a photo mask by using a dry-etching or wet-etching, thereby forming a plurality of ramparts 14 and insulating stripes 18 projecting in a direction parallel to the substrate; wherein the insulating stripes 18 are formed on the ramparts 14 and thus overhanging portions 185 are formed since the insulating stripes 18 are wider than the ramparts 14; forming a shadow mask onto top surfaces of the insulating stripes 18, exposing only the overhanging portions 185 and the openings between the overhanging portions 185; forming an organic layer 16 by deposition onto the substrate 10 and the first display electrodes 12, wherein the width of an organic layer 16 is larger than the distance between two overhanging portions 185; forming a plurality of second electrodes 17 by deposition onto the organic layer 16; and finally, forming an protective sealing layer 19 on at least the second display electrodes. In addition, a first reflective layer 22 is further formed on the protective sealing layer 19, so that the light generated can be focused and emitted in the direction towards the substrate 10. However, a second reflective layer 24 can also be formed on the bottom surface of the substrate 10, so as to increase the luminescence efficiency.
Even though this prior art provides an organic EL display panel and method for manufacturing the same, which can prevent a short-circuit between the edge of the first electrode and the second electrode and also improve the precision of matrix grid positioning, however, there are still some problems, related to heat and moisture, left unsolved.
In addition, this prior art provided ramparts 14 and the insulating stripes 18 are formed by nonmetallic insulating material or photoresist polymer material. During the procedure, the nonmetallic material or the polymer material easily absorb the outside humidification or moisture. After forming a protective sealing layer 19, the humidification or moisture in ramparts 14 and the insulating stripes 18 will release. Therefore, it will seriously influence the luminescence efficiency and the lifetime of the OLED device.